Class 0 | No ossifications. |
• Class I | Islands of bone within the periarticular soft tissues. |
• Class II | Bone spurs from the pelvis and/or proximal end of the femur (greater trochanter), leaving ≥1 cm between opposing surfaces. |
• Class III | Bone spurs from the pelvis and/or proximal end of the femur (greater trochanter), reducing the space between opposing bone surfaces to <1 cm. |
• Class IV | Apparent ankylosis of the hip. |